Objective To evaluate the relationship between haemorrhoids and Graves' disease (GD). Setting Using the nationwide data from Taiwan's Longitudinal Health Insurance Database. Participants We conducted a retrospective study, stratified patients by International Classification of Diseases, Ninth Revision, Clinical Modification disease code and compared the incidence rate of GD between patients with and without haemorrhoids. The study period was from 2000 to 2010, with exclusion of patients with diagnosed haemorrhoids before 2000 or after 2009, and we analysed the HR of GD in the univariable and multivariable models as well as the cumulative incidence curves of GD by using Kaplan-Meier curves. Result This study included 13 165 and 52 660 patients with and without haemorrhoids, respectively. The mean follow-up duration was approximately 6 years. The incidence rate of GD was 1.57 and 1.13 per 1000 person-years in patients with and without haemorrhoids, respectively. The area under the cumulative incidence curve of GD in patients with haemorrhoids was higher than that of patients without haemorrhoids. The risk of GD increased by 1.39 times (95% CI 1.13 to 1.71) in patients with haemorrhoids compared with patients without haemorrhoids. In the subgroup analysis, women with haemorrhoids had a higher risk of GD (adjusted HR 1.44; 95% CI 1.13 to 1.83). Patients with haemorrhoids aged 30-39 years were more likely to develop GD (adjusted HR 1.73; 95% CI 1.18 to 2.55). Conclusion The findings of this study indicate that patients with haemorrhoids may have an increased risk of GD compared with other potential confounding factors.
